The present disclosure relates to the field of tapping devices as used in the harvest of sap from maple trees. Current systems for the collection of sap from maple trees include plastic taps connected to plastic tubing, or lines. The tap is pressed into a hole that is drilled into the tree trunk, with maple sap flowing through the inner diameter of the tap. The lines are routed to a collection tank, which typically receives multiple lines from different trees. The system of lines may be configured in a branch and trunk manner, with smaller lines from taps joining larger lines, with the larger lines routing to a tank.
A vacuum system may also be included, which creates negative pressure in the lines and may increase the flow of sap from a tree. Natural vacuum systems rely on the slope of the collection lines to creature negative pressure, while artificial vacuum systems employ a vacuum pump.
Taps are typically installed to maple trees during winter months, before sap begins flowing. The procedure typically involves boring a hole in the tree trunk, and inserting a tap into the hole. The tap may need to be driven into the hole with a mallet. A collection line is then attached to the tap. At the end of the sugaring season, each tap is typically removed from the tree. Taps are typically molded from plastics such as nylon or polycarbonate.
The build-up of bacteria inside the tap is a significant problem, as bacteria build-up greatly reduces sap flow rates, as confirmed by a number of scientifically-rigorous studies. One study showed that 40.2% of sap yields can be explained by spout/adaptor age, with an average loss of 7.3 gallons per tap. Reusing taps causes a significant reduction in sap yields. The same study showed that aged lines have much less of an effect on saps yields than do aged taps. Taps that include a check valve also showed significant reduction in sap yields from year-to-year, with additional studies showing similar results.
One practice is to clean the inside of each tap, for example with a brush and cleaning fluid, prior to installing the tap in a tree. In addition to being laborious, cleaning has also been found to be at least somewhat ineffective at removing bacteria build-up inside a tap. Disposing of a tap after a single season of use avoids the problem of bacteria build-up, but is of course both wasteful and costly.
Additionally, there is evidence that a smaller inner diameter for a tap or tubing may increase sap yields, by improving the natural vacuum effect of the system. Additionally, there is evidence that the tap material that sap flows through has an effect on sap yields. That is, tap materials with different coefficients of friction and other properties may produce different sap yields.